1. Field of the Invention
The present invention relates to audio equipment for modifying the frequency characteristics of an audio signal generated by an external audio source. More specifically, the present invention pertains to audio equipment simulative of musical instruments, which allows a user to simulate the playing of music reproduced from an external audio source. The present invention allows a user to quickly modify the amplification of a given audio band pass frequency by selecting a first trigger associated with that band pass frequency, and subsequently activating a second trigger to amplify or attenuate the selected band pass frequency. The present invention may be shaped and configured to resemble any musical instrument, such as a guitar.
2. Description of the Prior Art
For many non-musicians, the inability to actively interact with music, i.e., the inability to perform as an actual musician, is often frustrating. Non-musicians' only interaction with pre-recorded or live musical performances is that of a passive listener. It is this inability to actively "join in" with the production of music that causes frustration on the part of many non-musicians.
In many instances, the only recourse for non-musicians to become more actively involved with a musical performance is to mime the actions of the musicians themselves. For instance, many an untrained classical music aficionado has "conducted" the symphony while the stereo played their favorite piece. And countless would-be rock-and-roll guitarists have sequestered themselves far from public view, set the stereo to its maximum level, and thrashed an imaginary "air guitar" in emulation of their favorite performers.
The present invention addresses the frustration of non-musicians by providing an apparatus which allows a user to directly influence the presentation of any piece of recorded music. The invention requires no knowledge of music, nor the ability to play a musical instrument. In essence, the present invention allows a user to re-mix the balance of frequencies in a pre-recorded musical performance while the pre-recorded piece is being played from an external audio source.
A multitude of U.S. patents describe apparatus for storing, modifying, and reproducing electrical signals which encode audio information. For instance, U.S. Pat. No. 4,957,031, issued Sep. 18, 1990, to M. Kondo et al., describes an automatic recording and playback apparatus having plural tone generating channels separately assignable to different parts of a musical piece. In essence, this device is a conventional multitrack Fecorder. The device allows a variable number of tracks or channels to be assigned in the recording and playback of audio signals. Selected parts of the recording can be recorded or played back separate from the other parts of the recording.
U.S. Pat. No. 5,148,484, issued Sep. 15, 1992, to J. Kane et al., discloses an audio signal processing unit for separating vocal signals from non-voice signals in a combined audio signal stream.
U.S. Pat. No. 5,298,674, issued Mar. 29, 1994, to S. L. Yun, describes a device similar in function to the Kane device. This reference describes a device for discriminating between a vocal audio signals and non-vocal audio signals. A combined vocal/instrumental signal is first pre-filtered to separate unambiguous vocal frequencies from unambiguous instrumental frequencies. An intermediate decisional logic circuit then analyzes the remaining frequencies to determine if the frequencies are attributable to vocal sources or instrumental sources.
U.S. Pat. No. 5,248,845, issued Sep. 28, 1993, to D. C. Massie et al., discloses a digital sampling instrument, i.e. a digital sampling synthesizer. The instrument allows for the synthesis of sounds imitative of acoustic instruments by recording a digital sample of the waveform of the actual instrument to be emulated. Specifically, the device addresses problems encountered when the sampled waveform of a given instrument is transposed up or down in pitch. If the waveform is transposed in pitch too far from its actual recorded pitch, undesirable waveform shifts result. These waveform shifts deteriorate the fidelity of the sound produced from the transposed waveform, resulting in an unnatural sound known as "munchkinization."
U.S. Pat. No. 5,210,366, issued May 11, 1993, to R. O. Sykes, Jr., describes a device for separating the individual voices in a musical composition preformed by a plurality of instruments. The entire combined signal frequency spectrum is compared to steady-state frequency representations for each instrument included in the performance. Frequencies which approximate the steady-state frequency representations are isolated and further comparisons are made to analyze the isolated frequencies during the growth, steady-state, and decay periods of the waveform signal. Once an acceptable match is found between an isolated waveform and a steady-state representation for a given instrument, the isolated waveform is recorded, and converted into an electrical signal which is output as musical data for a single voice of the combined signal.
U.S. Pat. No. 5,323,467, issued Jun. 21, 1994, to D. J. Hermes, discloses a device for separating an audio signal into a plurality of parallel band pass channels. In each frequency channel, the envelope of the signals found within that channel are detected, and the envelope preferentially filtered to enhance the signals at the frequency of the sound desired. The filtered channel outputs are then summed.
None of the above references, taken alone, or in any combination, is seen to describe the present invention.